Examples of such phosphors are disclosed in U.S. Pat. Nos. 4,225,653, 4,387,141, 4,959,174 and 4,970,024, the disclosures of which are incorporated herein by reference.
X-ray phosphors are used in medical intensifier screens to intensify x-ray images for x-ray films. It is known in the field of x-ray intensifier screens that larger particle size phosphors generally absorb more x-rays and render higher light output thereby reducing the x-ray dose to the patient. However, screens made with larger particle size phosphors have inherently poorer image resolution. Screens made with smaller particle size phosphors provide better resolution but have a lower light output thereby requiring higher x-ray doses. Consequently, it is generally known in the field to mix larger particle size phosphors with smaller particle size phosphors to achieve higher efficiency screens while minimizing the loss of resolution. Therefore, it would be an advantage to those persons working in the field of x-ray intensifier screens to provide a method which would increase the brightness or particle size, or both, of the phosphors used in x-ray intensifier screens.